Buffy the Vampire Slayer: Lessons(2002) [Dead Girl]: Appears to Michelle Trachtenberg as a ghost, claiming to have been killed by a werewolf; it's later revealed that she and the other "ghosts" are actually illusions manifested by a talisman, but I'll go ahead and list this just in case.

Jimmy and Judy(2006) [Judy]: Killed in a car crash, along with Edward Furlong, when she drives through a police roadblock; her body is shown afterwards in the wreckage, shown through the viewpoint of her video camera. (Thanks to Kelli)

Drive Thru(2007) [Starfire]: Killed (off-screen) by Van De La Plante in John Gilbert's garage; her body is shown afterwards when Penn Badgley discovers her in a freezer. (Thanks to Cody)